The Roentgen Standard
The oldest version of the "radioactive money" idea I have come across is an essay by SF writer Larry Niven, called "The Roentgen Standard".
It explains a lot of the knock-on effects, including why rich people will still want gold.
You can read it online here: http://www.larryniven.net/stories/roentgen.shtml
Biting the hand that feeds IT
